Improvement in the manufacture of paper



UNITED STATES PATENT OFFICE.

JOHN W. DIXON, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN THE MANUFACTURE OF PAPER.

Specification forming part of LettersPatent No. 51,568, dated December 19, 1865.

To all whom it may-concern:

Be it known that I, JOHN \V. DIXON, of the city of Philadelphia and State of Pennsylvania, haveinvented anew and useful Improvement in the Process of Making Paper-Pulp from \Vood, Straw, Oornstalks, and other Vegetable Fibrous Substances; and I do hereby declare the following to be a full and exact description of the same.

I cut the wood, straw, cornstalks, 850., into short lengths by any convenient cutting-machine. The cuttings are then placed in a strong closed boiler or digester and submitted to the action of a solution of the common soda-ash (carbonate of soda) of commerce. Boiling in this solution of soda-ash under pressure is of essential importance. By the words under pressure? is meant a pressure at, near, or above 300 of Fahrenheits scale, which is as low as is advisable to work the process. With wood I find a solution of 6 Baum, at a pressure of one hundred and twenty-five pounds and the corresponding temperature thereto, will complete the pulping operation in about eight to twelve hours. Aless strength ofsolution atthis temperaturesay from 2 to 4 of Baumwill answer with straw, cornstalks, or sorghum, and Iindicate these temperatures and strengths respectively in a good digesting apparatus, such as hereinafter described. I prefer, also, to perform the digesting operation under pressure in the peculiar apparatus for which I have-- applied for a patent, in which the boiling liquor under pressure, containing the soda-ash, is made to circulate from the bottom to the top of the digester and through the mass to be pulped within the digester by means of a pump.

Heatmay be communicated by a coil of steam or hot-watcr pipes in the bottom of the digester or any other convenient mode.

After the material has been thus heated it is-to be Washed in the usual way and then bleached with chlorine or chloride of lime in the usual way.

I do not desire to limit myself to the above degrees of temperature for treating the material, nor the above strength of solution, nor to any special form of pulp-digesting apparatus. The heat of the llQlllLI'SOltlI-IOH in the digester may be varied from 300 to 400 Fahrenheit, according to the nature of the substance to be heated, the length of time under treatment, and the form of digesting apparatus adopted.

Having thus described my invention, what I claim as new, and desire to secure by Let ters Patent, is-

The process of treating wood or other vegetable's'ubstances by boiling in soda-ash (carbonate of soda) under pressure, as a process,

or preparatory process, for making pulp for the manufacture of paper from wood, straw, or other vegetable fibrous substances, substantially as described.

In witness whereof I have hereunto set my hand this 1st day of December,'A. D. 1865.

JOHN W. DIXON.

Witnesses J. ROBERTS HOWELL, GEO. BUOKLEY. 

